In this paper, we report our development on making of nanoscale silver pastes and their low-temperature sintering for semiconductor device interconnections. The nanoscale silver pastes were prepared by dispersing 30-nm silver powder under ultrasonic vibration and mechanical agitation in an organic vehicle. Sintering of the silver paste prints at 280°C for 10 minutes resulted in a density of ~80% in the air ambient. Some important properties of the low-temperature sintered silver include ~2.4 W/K-cm for thermal conductivity, ~3.8 × 10−6 Ω-cm for electrical resistivity, and ~9 GPa for the effective elastic modulus. SiC Schottky rectifiers attached to either silver- or gold-coated direct bond copper (DBC) substrates show low forward voltage drops. The silver joints do not contain large voids but rather uniformly distributed microscale pores. Die-shear tests showed that bonding strengths of the silver joints were around 21 MPa on the gold-coated DBC substrates and 38 MPa on the silver-coated DBC substrates, respectively. The latter is comparable to that of reflowed eutectic lead-tin solder joints. Based on the findings in this work, the low-temperature sintering of nanoscale silver pastes is promising to be a high performance and highly-reliable semiconductor device bonding solution for high power packages.

1.
R. R. Tummala, P. Garrou, T. K. Gupta, N. Kuramoto, K. Niwa, Y. Shimada, M. Terasawa, in Microelectronics Packaging Handbook: Semiconductor Packaging, Part II, R. R. Tummala, E. J. Rymaszewksi, A. G. Klopfenstein, Eds. Chapman & Hall (New York, 1997), pp. 285–293.
2.
Bindra
A.
, “
BGA MOSFETs keep their cool at high power levels
,”
Electronic Design
,
47
(
19
), p.
43
43
,
1999
.
3.
International Rectifier Corp. News Release, El Segundo, California, June 9, 2000.
4.
Bindra
A.
, “
Innovative package maximize MOSFETs’ thermal performance
,”
Electronic Design
,
47
(
10
), pp.
52
64
,
1999
.
5.
Mannion
P.
, “
MOSFETs break out of the shackles of wire bonding
,”
Electronic Design
,
47
(
6
), p.
36
36
,
1999
.
6.
A. Sawle, M. Standing, T. Sammon, and A. Woodorth, “DirectFET-a proprietary new source mounted power package for board mounted power,” International Rectifier Corp. Oxted, Surry, England.
7.
Kim
H. K.
,
Liou
H. K.
, and
Tu
K. N.
, “
Three-dimensional morphology of a very rough interface formed in the soldering reaction between eutectic SnPb and Cu
,”
Appl. Phys. Lett.
, vol.
66
, pp.
2337
2339
,
1995
.
8.
Neudeck
P. G.
,
Okojie
R. S.
, and
Chen
L. Y.
, “
High-temperature electronics - A role for wide bandgap semiconductors?
Proc. IEEE
, vol.
90
, pp.
1065
1076
,
2002
.
9.
Schmid
U.
,
Sheppard
S. T.
, and
Wondrak
W. A.
, “
High temperature performance of NMOS integrated inverters and ring oscillators in 6H-SiC
,”
IEEE Trans. Electron Devices
, vol.
47
, pp.
687
691
,
2000
.
10.
Cooper
J. A.
and
Agarwal
A.
, “
SiC power-switching devices - The second electronics revolution?
Proc. IEEE
90
, pp.
956
968
,
2002
.
11.
Sugawara
Y.
, “
SiC devices for high voltage high power applications
,”
Mat. Sci. For.
vol.
457–460
, pp.
963
968
,
2004
.
12.
Wondrak
W.
,
Held
R.
,
Niemann
E.
, and
Schmid
U.
, “
SiC devices for advanced power and high-temperature applications
,”
IEEE Trans. Indus. Electron
. vol.
48
, pp.
307
308
,
2001
.
13.
Khan
M. A.
,
Chen
Q.
,
Shur
M. S.
,
Dermott
B. T.
,
Higgins
J. A.
,
Burm
J.
,
Schaff
W. J.
, and
Eastman
L. F.
, “
GaN based heterostructure for high power devices
,”
Solid- State Electron.
, vol.
41
, pp.
1555
1559
,
1997
.
14.
Endriz
J. G.
,
Vakili
M.
,
Bowder
G. S.
,
DeVito
M.
,
Haden
J. M.
,
Harnagel
G. L.
,
Plano
W. L.
,
Sakamato
M.
,
Welch
D. F.
,
Willing
St.
,
Vorland
D. P.
, and
Yao
H. C.
, “
High-power diode-laser arrays
,”
IEEE J. Quantum Electron.
, vol.
28
, pp.
952
965
,
1992
.
15.
Katz
A.
,
Lee
C. H.
, and
Tai
K. L.
, “
Advanced metallization schemes for bonding of InP-based laser devices to CVD-diamond heatsinks
,”
Mat. Chem. Phys.
, vol.
37
, pp.
303
328
,
1994
.
16.
Tessmer
A. J.
,
Plano
L. S.
, and
Dreifus
D. L.
, “
High-temperature operation of polycrystalline diamond field-effect transistors
,”
IEEE Electron. Dev. Lett.
, vol.
14
, pp.
66
68
,
1993
.
17.
Werner
M. R.
and
Fahrner
W. R.
, “
Review on materials, microsensors, systems, and devices for high-temperature and harsh-environment applications
,”
IEEE Trans. Ind. Electron.
, vol.
48
, pp.
249
257
,
2001
.
18.
Liu
X. S.
,
Hu
M. H.
,
Nguyen
H. K.
,
Caneau
C. G.
,
Rasmussen
M. H.
,
Davis
R. W.
, and
Zah
C.-E.
, “
Comparison between Epi-Down and Epi-Up Bonded High Power Single-Mode 980 nm Semiconductor Lasers
,”
IEEE Trans. Adv. Pack.
, Vol.
27
, pp.
640
646
,
2004
.
19.
Rane
S.
,
Puri
V.
, and
Amalnerkar
D.
, “
A study on sintering and microstructure development of fritless silver thick film conductors
,”
J. Mater. Sci. - Mater. Electron.
, vol.
11
, pp.
667
674
,
2000
.
20.
Chang
C. R.
, and
Jean
J. H.
, “
Effects of silver-paste formulation on camber development during the cofiring of a silver-based, low-temperature-cofired ceramic package
,”
J. Am. Cer. Soc.
, vol.
81
, pp.
2805
2814
,
1998
.
21.
Manepalli
R.
,
Stepniak
F.
,
Bidstrup-Allen
S. A.
, and
Kohl
P. A.
, “
Silver metallization for advanced interconnects
,”
IEEE Trans. Adv. Pack.
, vol.
22
, pp.
4
8
,
1999
.
22.
H. Schwarzbauer, “Method of securing electronic components to a substrate,” U.S. Patent 4 810 672.
23.
Schwarzbauer
H.
and
Kuhnert
R.
, “
Novel large area jointing technique for improved power device performance
,”
IEEE Trans. Ind. Appl.
Vol.
27
, pp.
93
95
.
24.
Zhang
Z.
and
Lu
G. Q.
, “
Pressure-assisted low-temperature sintering of silver paste as an alternative die-attach solution to solder reflow
,”
IEEE Trans. Electron. Pack. Manu.
, vol.
25
, pp.
279
283
,
2002
.
25.
Chuang
R. W.
and
Lee
C. C.
, “
Silver-indium joints produced at low temperature for high temperature devices
,”
IEEE Trans. Comp. Pack. Tech.
vol.
25
, pp.
453
458
,
2002
.
26.
Groza
J. R.
and
Zavaliangos
A.
, “
Nanostructured bulk solids by field activated sintering
,”
Rev. Adv. Mater. 0Sci.
vol.
5
, pp.
24
33
,
2003
.
27.
Groza
J. R.
, “
Nanosintering
,”
NanoStruct. Mater.
, vol.
12
, pp.
987
992
,
1999
.
28.
Parker
W. J.
,
Jenkins
R. J.
,
Butler
C. P.
, and
Abbott
G. L.
, “
Flash method of determining thermal diffusivity, heat capacity, and thermal conductivity
,”
J. Appl. Phys.
, vol.
32
, pp.
1679
1684
,
1961
.
29.
Hasselman
D. P. H.
and
Donaldson
K. Y.
, “
Effects of detector nonlinearity and specimen size on the apparent thermal-diffusivity of nist-8425 graphite
,”
Int. J. Thermophys.
, vol.
11
, pp.
573
585
,
1990
.
30.
The websites of IXYS Inc.: www.IXYS.com
31.
Sonix Inc.: www.sonix.com.
32.
Kester product datasheet: www.kester.com
33.
Choe
J.
,
Calata
J. N.
, and
Lu
G. Q.
, “
Constrained-film sintering of a gold circuit paste
,”
J. Mater. Res.
, vol.
10
, pp.
986
994
,
1995
.
34.
Levin
V. A.
,
Lokhin
V. V.
, and
Zingerman
K. M.
, “
Effective elastic properties of porous materials with randomly dispersed pores: finite deformation
,”
J. Appl. Mech.
, vol.
67
, pp.
667
670
,
2000
.
35.
J. G. Bai, Z. Zhang, G.Q. Lu, and D.P.H. Hasselman, “Characterization of solder/copper interfacial thermal resistance by the flash technique,” To appear in Int. J. Thermophys.
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